Gfci

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keith gigabyte

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Here's a bizarre one. Residential kitchen..call for gfci tripping. Pull GFCI out of wall, inspect wiring. Seems fine 1 set line wires 2 sets load. Confirm line is connected to line. Disconnect load wires, still trips... Install new GFCI no load wires still trips. Figure I had a bad one. Get new one different brand. Still tripping with just line connected. Double check wiring. Black to white 120 volts black to ground 120 volts continuity white to ground.
Stumped here
 
So with only the line terminals connected it is tripping? Is there anything plugged into the receptacle at that time? Could the load terminals be coming in contact with anything while pushed in the box?
 
What work was done in the house before this started?
What's new?

You can check for voltage neutral to ground so see if there's some stray voltage on something.
 
I suspect the husband !

Maybe just because I've had a couple service calls recently where the husband replacing outlets was the problem....
 
dmxtothemax said:
any new appliances recently installed ?
Anywhere in the house ?
Ditto any handyman and or electrical work ?
anywhere !
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There should be nothing a handyman could do that would cause a GFCI to trip that has no load side connections.

The OP tested and each of the three conductors connected to the supply side of the GFCI show the correct readings.

This is a very odd problem.
 
Find the circuit breaker it is on and turn it off. I know it's supposed to be a kitchen counter but see if there is anything else is on that circuit and work your way backward. You're right, this is kind of strange. Irrespective of whether there is anything on the circuit before this GFCI there should be no reason it should trip.

Just thought of something else to check. If its a metal JB, with your VOM check to see if there's any voltage between the JB and the neutral. Just because it's a metal JB doesn't mean it's properly grounded. I've had a situation where a caretaker of an elderly woman got whacked getting a glass of water from the kitchen sink. She touched the faucet and the outer rim of the sink. It turned out that none of the BX cables feeding the kitchen were properly grounded. There must have been a disconnect somewhere between the panel and the first JB but all the armored cables became energized due to a defective light switch.

Good luck.
 
1793 said:
What is the wiring method? Have you tested to see if the GFI holds while out of the wall, not connected to the box?
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If the box is ungrounded and live would it not trip the breaker with the GFCI in the box?

keith gigabyte said:
Double check wiring. Black to white 120 volts black to ground 120 volts continuity white to ground.
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I have to say I am stumped on this if the readings are correct.
 
keith gigabyte said:
Here's a bizarre one. Residential kitchen..call for gfci tripping. Pull GFCI out of wall, inspect wiring. Seems fine 1 set line wires 2 sets load. Confirm line is connected to line. Disconnect load wires, still trips... Install new GFCI no load wires still trips. Figure I had a bad one. Get new one different brand. Still tripping with just line connected. Double check wiring. Black to white 120 volts black to ground 120 volts continuity white to ground.
Stumped here
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When all else fails then turn to logic. With proper reading on the line conductors it's impossible for the GFCI to trip ( if it's hooked up correctly). What's left ?

The odds against getting two bad GFCI receptacles in a row is probably one in a billion but not impossible.

I would try still another GFCI receptacle. Or call in a priest to do an exercisem ( probably didn't spell that right )
 
1793 said:
You would think and I am too. Just trying to get the troubleshooting juices flowing.:?
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I hear you and I was not trying to give you a hard time. :) It is just an odd problem.

I guess if it was me I would get an extension cord, plug it in to a known good source, ideally a plug at the panel you can see the wiring for. Bring the other end of the cord to the outlet location and use the cord and a meter to retest the existing branch circuit for proper voltage continuity with a meter that does not respond to phantom voltages.

Yet even while typing the above I keep thinking 'nothing on the line side can trip a GFCI'.

I am stumped. :?
 
When you say "still trips". you're talking about multiple trips past the initial one that forces you to test it, yes? Are you hooking up polarity correctly? Have a practical joker that might swap the load side sticker to line side terminals? Maybe someone returned damaged GFCIs to the same supply house and you are the unlucky customer to get them?

eta: reading the these new self test gfci... you sure you have the line side neutral paired with the line side hot? small box, 3 sets of wire, might be easy to get them crossed up.
 
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JFletcher said:
When you say "still trips". you're talking about multiple trips past the initial one that forces you to test it, yes? Are you hooking up polarity correctly? Have a practical joker that might swap the load side sticker to line side terminals? Maybe someone returned damaged GFCIs to the same supply house and you are the unlucky customer to get them?

eta: reading the these new self test gfci... you sure you have the line side neutral paired with the line side hot? small box, 3 sets of wire, might be easy to get them crossed up.
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I know its extremely unlikely (and gfci isn't supposed to be as susceptible to it nowadays) but maybe rf or some other ghost?
 
user 100 said:
I know its extremely unlikely (and gfci isn't supposed to be as susceptible to it nowadays) but maybe rf or some other ghost?
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If I were to gamble on this one, I'm going with the hooked up line side neutral isnt line side... odds of two gfci being bad are astronomical (aside from previously mentioned returns) older gfci could operate with all kinds of wiring errors, i ran into a kitchen gfci last year that was wired backward on hot (line/load reverse) with crossed up neutrals... still tested and reset and powered downstream receptacles, but wouldnt trip a gfci tester. I made the mistake of assuming it was wired right and just had failed, so when I wired the new one in, it didnt work. Rewired it the right way, still didnt work... the one I grabbed from the truck was bad...wasnt in a box... asked the boss he pulled it from another job... that's why I refuse to put used electrical parts anywhere other than the trashcan...if I dont have one I take a sharpie and put a big X across the face of something like that so I never waste another hour installing a broken part.

It's very easy in a cramped jbox to mistrace a wire. Hypothetically, If there were two circuits in that jbox, using the neutral from one and the hot from the other (both line side), what would happen? I know a GFCI breaker would fail but the receptacle doesnt care about upstream, as long as all the wiring is actually upstream. With no loads connected, either wiring or plugged in, the GFCI should hold. Now, an AFCI breaker will trip if there is a problem even when as small a load as a GFCI LED test light comes on, but OP mentioned nothing of that.

eta: it would be very useful to know how these new self testing GFCI work. I'd assume that they send an x ma signal across from hot to neutral and measure it, and if it's within spec, it goes on its merry way until the next self test. a broken neutral might cause it to fail the test but op said he had continuity between ground and neutral, so that's not it.
 
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If you have continuity between neutral and ground, it's not possible the line side neutrals are crossed unless you have a bond somewhere downstream that shouldn't be there. Is this possibly a MWBC? If so, there is a possibility that you have an issue on the other side of that MWBC that is inversely spiking the voltage, and that will cause it to trip. Can you keep a meter on it and measure max voltage L/G when it trips?


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I think the best advice so far is to try it out of the box.

A step further would be to first prove the GFCI is working on a known good and/or different circuit.
 
brantmacga said:
If you have continuity between neutral and ground, it's not possible the line side neutrals are crossed unless you have a bond somewhere downstream that shouldn't be there. Is this possibly a MWBC? If so, there is a possibility that you have an issue on the other side of that MWBC that is inversely spiking the voltage, and that will cause it to trip. Can you keep a meter on it and measure max voltage L/G when it trips?


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Good points. I'd guess a voltage sag might give the same trips? OP had 120V on hot tho, a most unusual reading with a lost neutral on a MWBC unless it was completely unloaded.

Every house/apt of some age that we've installed AFCI details about 5 minutes of installing the breaker, and spending 1-3 hours tracking down all the crossed neutrals causing it to trip. May be our luck or the area. My only point is that having continuity between neutral and ground does not automatically guarantee that you have the line side neutral.
 
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